EP 0148482 A (DAIKIN IND LTD) relates to halogen-containing PFPEs which are said to be suitable for a variety of uses, e.g. lubricants. This document discloses, inter alia, a halogen-containing PFPE having formula [formula (XII) on page 5, lines 18-26]:A(CH2CF2CF2O)p[CF(CF3)CF2O]qCF(CF3)COFwherein:p is an integer of 2 to 200 and q is an integer of 0 to 50 andA is F, Br, I or it can be a group of formula:RfCF2O—or a group of formula:Rf′O—(CF(CF3)CF2O)p+1 in which Rf and R′f can represent a perfluoroalkyl group having from 1 to 10 carbon atoms and p is an integer of 0 to 50 [formulae (VIII) and (IX) on page 4, lines 19-22].
U.S. Pat. No. 4,904,417 (DAIKIN IND LTD) discloses the reaction of compounds of formula A-(CF2CF2)m-A′, wherein m is an integer from 1 to 6 and A and A′ are, possibly, COF, with 2,2,3,3-tetrafluorooxethane in the presence of fluoride anions as polymerization initiators, to yield derivatives having COF end groups.
U.S. Pat. No. 6,136,331 (DAIKIN IND LTD) U.S. Pat. No. 6,136,331 to Daikin discloses cosmetic compositions comprising compounds of formula XO—[CF(CF3)2O]h(CF2CF2O)o—Y—COOR3, wherein h+o ranges from 1 to 100, X can be H, F, Cl, Br, or at least partially fluorinated alkyl group, Y is a partially or completely fluorinated alkyl group, and R3 is a C1-C22 aliphatic group. These compounds can be notably manufactured by reaction of a hexafluoropropylene oxide oligomer having acyl fluoride end groups and 2,2,3,3-tetrafluorooxethane in the presence of a catalyst, and subsequent reaction of the compound obtained therefrom to derivatize the COF end group with an alcohol compound or by fluorination. The catalyst can be notably KF, CsF. Preparative example 5 discloses, for instance, the reaction of a HFPO dimer [C3F7O—CF(CF3)FCOF] with 2,2,3,3-tetrafluorooxethane and CsF and subsequent reaction with methanol to yield a compound of formula: C3F7OC(CF3)FCF2O—(CH2CF2 CF2O)n—CH2CF2—COOCH3 with n˜10.
JP 2003231719 (DAIKIN IND LTD) discloses certain fluoroelastomers comprising recurring units derived from particular vinyl ether compounds; among the synthetic methods used in the exemplified working embodiments of this application for manufacturing said recurring units, use is made of the reaction of 2,2,3,3-tetrafluorooxethane to provide acyl fluoride compounds, more precisely I—CH2CF2—COF and Cl—CH2CF2—COF.
US 2006281946 (DAIKIN IND LTD) describes the synthesis of compounds of formula: Rf1—(OCH2CF2CF2)n1OCX1X2CF2(Rf2)n2—COOM wherein Rf1 is a straight or branched fluoroalkyl group containing 1 to 20 carbon atoms, optionally containing 1 to 5 oxygen atoms in the main chain, by ring-opening polymerization reaction of an acyl fluoride derivative of formula Rf3—COF with 2,2,3,3-tetrafluorooxethane, wherein Rf3 is a straight or branched fluoroalkyl group containing 1 to 20 carbon atoms, optionally containing 1 to 5 oxygen atoms in the main chain.
Similarly, JP 2009173644 (DAIKININD LTD) discloses a method for manufacturing compounds of formula: Rf1—(OCH2CF2CF2)n1OCX1X2CF2 (Rf2)n2—COOM by ring-opening polymerization of 2,2,3,3-tetrafluorooxethane onto an acyl fluoride derivative of formula Rf3—COF, wherein Rf3 is a fluoroalkyl group optionally containing 1-5 oxygen atoms.
None of the above documents discloses or suggests to prepare block copolymers using acyl fluorides of (per)fluoropolyethers complying with certain molecular weight requirements as precursors to be used as oils with improved anti-wear properties or with improved hydrophobic or oilophobic properties.